Updated characteristics of marine mammals habitats

in the Chukchi Sea and adjoining waters



Nikita Platonov

A. N. Severtsov Institute of Ecology and Evolution of Russian Academy of Sciences, Moscow (󠀠IEE RAS󠀠)


The 26th Meeting of the Marine Mammals Working Group
Anchorage, 01 February 2020
pdf version

Methodology

Sea ice phenology

Timeseries of marginal sea ice zone

Timeseries of marginal sea ice zone

Sea ice phenology

Approximation of sea ice concentration timeseries by monotonos function.

Approximation of sea ice concentration timeseries by monotonos function.

Use an argument (date) when monotonuos function intersects sia ice concentration 15% constant value.

Sea ice phenology

Single-layered map instead of multi-layered map of timeseries

Single-layered map instead of multi-layered map of timeseries

One map instead of map series, but only ice extent by sea ice concentration level 15% is figured.

Sea ice phenology

Contouring displaying as additional layer

Contouring displaying as additional layer

Isochromes are better for visual analysis of phenology rate. Higher density of isochrones means slow rate of retreat or advance. Slow rate of sea ice retreat doesn’t force high locomotion near ice edge.

Smoothing of input phenology maps is desirable.

Sea ice phenology

Distance between contour lines per fixed time interval

Distance between contour lines per fixed time interval

Slope/elevation GIS tools are used to generate rate maps with distinguish that day/meter not meter/meter relation is used to calculate slope.

Sea ice phenology

Rate and direction of ice status change

Rate and direction of ice status change

Arrows are normal to isochrones.

Results

Rate of sea ice retreat

Rates of sea ice disappearance in 2016-2019

Rates of sea ice disappearance in 2016-2019

Rate of sea ice retreat

Longterm (2003-2019) mean, variability and trends of sea ice disappearance rate

Longterm (2003-2019) mean, variability and trends of sea ice disappearance rate

Rate of sea ice advance

Longterm (2004-2019) mean, variability and trends of sea ice appearance rate

Longterm (2004-2019) mean, variability and trends of sea ice appearance rate

Ice-covered season length

Length of ice-covered period based on sea ice disappearance and appearance dates. Contour is isochrone of 180 days [@Gormezano2015]

Length of ice-covered period based on sea ice disappearance and appearance dates. Contour is isochrone of 180 days (Gormezano and Rockwell, 2015)

Summary

  • Spatial profile: ice habitat decreasing,
    or temporal profile: Ice-covered season shortening

  • Extent of annual ice expands northern waters with insignificant change of ice edge rate (km/day).

  • Rate of sea ice appearance is higher then rate of sea ice disappearance.

Gormezano LJ, Rockwell RF. 2015. The energetic value of land-based foods in western Hudson bay and their potential to alleviate energy deficits of starving adult male polar bears. In: Dias J. M. (Ed) PLOS ONE, 10(6): e0128520. Public Library of Science (PLoS). 10.1371/journal.pone.0128520.